The percutaneous needle tenotomy in the treatment of tendon contractures in brain damaged patients: Pilot study

ObjectiveAssessment of the feasibility and efficacy of percutaneous needle tenotomy in patients with neuro-orthopedic disorders secondary to impairment of the central nervous system.Material and methodFourteen patients were followed in the Physical medicine and rehabilitation Department from September 2014 to March 2015. The average age was 58.7years (29–86 y). The origin of neuro-orthopedic disorder was stroke (n=7), parkinsonism (n=2), head trauma (n=2), cerebral palsy (n=1), Little's disease (n=1) and Alzheimer's disease (n=1). The indication of percutaneous needle tenotomy was selected during a medical-surgical consultation. Twenty-one goals were identified: hygiene (n=6), pain (n=4), sitting (n=3), standing (n=4), transfers (n=1), walking (n=2), grasping (n=1). A total of 31sites were covered: the finger flexors (n=9), the semitendinosus, biceps femoris and tensor fascia lata (n=7), the Achilles tendon (n=5), the biceps and brachioradialis (N=3), the wrist flexors (n=2), flexor digitorum longus (7claw toes) and hip adductors (n=1). In 10 patients the treatment involved several sites. Tenotomy was performed with a 18Gneedle (1,2×40mm), under local or regional anesthesia. A plaster cast was associated with hamstring tenotomy if the objective was functional. A cast was always associated with Achilles tendon, elbow flexor and wrist flexor tenotomy. The Goal Attainment Scale (GAS) was used to assess the effectiveness of treatment.ResultsThe targets were achieved in all cases (GAS≥0). No side effects were noted.DiscussionPercutaneous needle tenotomy is a technique which can be used as treatment of some neuro-orthopedic disorders in brain-damaged patients. Percutaneous tenotomy of the Achilles’ tendon has already been described by Minkowitz. Our study shows the feasibility and effectiveness of needle tenotomy, sometimes multi-site, performed in this type of patient

Tests of Non-Causality Under Markov Assumptions for Qualitative Panel Data

For many years, social scientists have been interested in obtaining testable definitions of causality [C. W. Granger (1969)]. Recent works include those of G. Chamberlain (1982) and J. P. Florens and M. Mouchart (1982). The present paper first clarifies the results of these latter papers by considering a unifying definition of non-causality. Then, log-likelihood ratio (LR) tests for non-causality are derived for qualitative panel data under the minimal assumption that one series is Markov. LR tests for the Markov property are also obtained. Both test statistics have closed forms. These tests thus provide a readily applicable procedure for testing non-causality on qualitative panel data. Finally, the tests are applied to French Business Survey data in order to test the hypothesis that price changes from period to period are strictly exogenous to disequilibria appearing within periods

Incentivizing High Quality Crowdwork

We study the causal effects of financial incentives on the quality of crowdwork. We focus on performance-based payments (PBPs), bonus payments awarded to workers for producing high quality work. We design and run randomized behavioral experiments on the popular crowdsourcing platform Amazon Mechanical Turk with the goal of understanding when, where, and why PBPs help, identifying properties of the payment, payment structure, and the task itself that make them most effective. We provide examples of tasks for which PBPs do improve quality. For such tasks, the effectiveness of PBPs is not too sensitive to the threshold for quality required to receive the bonus, while the magnitude of the bonus must be large enough to make the reward salient. We also present examples of tasks for which PBPs do not improve quality. Our results suggest that for PBPs to improve quality, the task must be effort-responsive: the task must allow workers to produce higher quality work by exerting more effort. We also give a simple method to determine if a task is effort-responsive a priori. Furthermore, our experiments suggest that all payments on Mechanical Turk are, to some degree, implicitly performance-based in that workers believe their work may be rejected if their performance is sufficiently poor. Finally, we propose a new model of worker behavior that extends the standard principal-agent model from economics to include a worker's subjective beliefs about his likelihood of being paid, and show that the predictions of this model are in line with our experimental findings. This model may be useful as a foundation for theoretical studies of incentives in crowdsourcing markets.Comment: This is a preprint of an Article accepted for publication in WWW \c{opyright} 2015 International World Wide Web Conference Committe

Microstructural Characterization of Graphite Spheroids in Ductile Iron

The present work brings new insights by transmission electron microscopy allowing disregarding or supporting some of the models proposed for spheroidal growth of graphite in cast irons. Nodules consist of sectors made of graphite plates elongated along a hai direction and stack on each other with their c axis aligned with the radial direction. These plates are the elementary units for spheroidal growth and a calculation supports the idea that new units continuously nucleate at the ledge between sectors

Tests of Non-Causality Under Markov Assumptions for Qualitative Panel Data

For many years, social scientists have been interested in obtaining testable definitions of causality [C. W. Granger (1969)]. Recent works include those of G. Chamberlain (1982) and J. P. Florens and M. Mouchart (1982). The present paper first clarifies the results of these latter papers by considering a unifying definition of non-causality. Then, log-likelihood ratio (LR) tests for non-causality are derived for qualitative panel data under the minimal assumption that one series is Markov. LR tests for the Markov property are also obtained. Both test statistics have closed forms. These tests thus provide a readily applicable procedure for testing non-causality on qualitative panel data. Finally, the tests are applied to French Business Survey data in order to test the hypothesis that price changes from period to period are strictly exogenous to disequilibria appearing within periods

Tests of noncausality under Markov assumptions for qualitative panel data

For many years, social scientists have been interested in obtaining testable definitions of causality (Granger 1969, Sims 1972). Recent works include those of Chamberlain (1982) and Florens and Mouchart (1982). The present paper first clarifies the results of these latter papers by considering a unifying definition of noncausality. Then, log-likelihood ratio (LR) tests for noncausality are derived for qualitative panel data under the minimal assumption that one series is Markov. LR tests for the Markov property are also obtained. Both test statistics have closed forms. These tests thus provide a readily applicable procedure for testing noncausality on qualitative panel data. Finally, the tests are applied to French Business Survey data in order to test the hypothesis that price changes from period to period are strictly exogenous to disequilibria appearing within periods

Inner Space Preserving Generative Pose Machine

Image-based generative methods, such as generative adversarial networks (GANs) have already been able to generate realistic images with much context control, specially when they are conditioned. However, most successful frameworks share a common procedure which performs an image-to-image translation with pose of figures in the image untouched. When the objective is reposing a figure in an image while preserving the rest of the image, the state-of-the-art mainly assumes a single rigid body with simple background and limited pose shift, which can hardly be extended to the images under normal settings. In this paper, we introduce an image "inner space" preserving model that assigns an interpretable low-dimensional pose descriptor (LDPD) to an articulated figure in the image. Figure reposing is then generated by passing the LDPD and the original image through multi-stage augmented hourglass networks in a conditional GAN structure, called inner space preserving generative pose machine (ISP-GPM). We evaluated ISP-GPM on reposing human figures, which are highly articulated with versatile variations. Test of a state-of-the-art pose estimator on our reposed dataset gave an accuracy over 80% on PCK0.5 metric. The results also elucidated that our ISP-GPM is able to preserve the background with high accuracy while reasonably recovering the area blocked by the figure to be reposed.Comment: http://www.northeastern.edu/ostadabbas/2018/07/23/inner-space-preserving-generative-pose-machine

Market Power and Collusion on Interconnection Phone Market in Tunisia : What Lessons from International Experiences

We try in this paper to characterize the state of mobile phone market in Tunisia. Our study is based on a survey of foreign experience (Europe) in detecting collusive behavior and a comparison of the critical threshold of collusion between operators in developing countries like Tunisia. The market power is estimated based on the work of Parker Roller (1997) and the assumption of "Balanced Calling Pattern". We use then the model of Friedman (1971) to compare the critical threshold of collusion. We show that the "conduct parameter" measuring the intensity of competition is not null during the period 1993-2011. Results show also that collusion is easier on the Tunisian market that on the Algerian, Jordanian, or Moroccan one